High Efficiency High Power Density Power Architecture Based on Buck-Boost Regulators with a Pass-Through Band

ABSTRACT

A power system comprising a non-isolated voltage regulator configured to couple to an input voltage and produce an output voltage, wherein the non-isolated voltage regulator is in a power distribution system and configured to boost the input voltage when the input voltage is less than a minimum output voltage, to reduce the input voltage when the input voltage is greater than a maximum output voltage, and to pass-through the input voltage when the input voltage is greater than or equal to the minimum output voltage and less than or equal to the maximum output voltage.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 61/376,994 filed Aug. 25, 2010 by Hengchun Mao, et al.and entitled “High Efficiency High Power Density Power ArchitectureBased on Buck-Boost Regulators with a Pass-Through Band,” which isincorporated by reference herein as if reproduced in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

The power system of electronic equipment needs to convert its inputpower to voltages acceptable to its load. The power system usuallyconsists of many modules and components, and the architecture of thepower system illustrates the interconnection of the said modules andmain components. Usually, the power system is divided into two parts:power distribution from the input source to a circuit card, and powerconversion on a circuit card. To reduce the voltage and current stressesof components on a circuit card, it is desirable to have one or morevoltage regulators in the power distribution. The voltage regulatorsconvert an input voltage from a power or voltage source to an outputvoltage within a voltage range that is suitable for the circuit cards ofthe electronics equipment. One or a plurality of voltage regulators canbe used to deliver regulated power or voltage to one or a plurality ofcircuit cards in electronics equipment. In many systems, the inputvoltage from the power source to the voltage regulators and the outputvoltage from the voltage regulators to the loads are both direct current(DC). Accordingly, a significant part of the power system is a DCsystem. In many applications, it is desirable to design or configure thepower system to operate at relatively high efficiency and providerelatively high power to electronics equipment. For example, the powersystem architectures may be optimized to reduce power consumption,provide stable and reliable operations, and/or reduce system space andthus system cost.

SUMMARY

In one embodiment, the disclosure includes a power system comprising anon-isolated voltage regulator in a power distribution system configuredto couple to an input voltage and produce an output voltage, wherein thenon-isolated voltage regulator is configured to boost the input voltagewhen the input voltage is less than a minimum output voltage, to reducethe input voltage when the input voltage is greater than a maximumoutput voltage, and to pass-through the input voltage when the inputvoltage is greater than or equal to the minimum output voltage and lessthan or equal to the maximum output voltage.

In another embodiment, the disclosure includes a non-isolated voltageregulator comprising a positive input lead, a positive output leadcoupled to the positive input lead, a negative input lead, a negativeoutput lead coupled to the negative input lead, a first switchingcomponent positioned between the positive input lead and the positiveoutput lead, and a second switching component positioned between thenegative input lead and the negative output lead.

In yet another embodiment, the disclosure includes a method comprisingcontrolling a first gate voltage in a first switching component on afirst power lead of a first non-isolated voltage regulator to controlcurrent on the first power lead, and controlling a second gate voltagein a second switching component on a second power lead of the firstnon-isolated voltage regulator to control current on the second powerlead, wherein each of the first power lead and the second power leadshares current with a third power lead of a second non-isolated voltageregulator coupled in parallel to the first non-isolated voltageregulator.

These and other features will be more clearly understood from thefollowing detailed description taken in conjunction with theaccompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is nowmade to the following brief description, taken in connection with theaccompanying drawings and detailed description, wherein like referencenumerals represent like parts.

FIG. 1 is a typical architecture of a power system.

FIG. 2 is another architecture of a power system.

FIG. 3 is an embodiment of a new architecture for a power system.

FIG. 4 is a chart of an embodiment of various operational modes.

FIG. 5 is a chart of another embodiment of various operational modes.

FIG. 6 is a schematic diagram of an embodiment of a voltage regulator.

FIG. 7 is a schematic diagram of an embodiment of a Buck converter.

FIG. 8 is a schematic diagram of an embodiment of a Boost converter.

FIG. 9 is a schematic diagram of an embodiment of a Buck-Boostconverter.

FIG. 10 is a schematic diagram of another embodiment of a Buck-Boostconverter.

FIG. 11 is a schematic diagram of another embodiment of a Buck-Boostconverter.

FIG. 12 is a schematic diagram of an embodiment of a new Buck-Boostconverter.

FIG. 13 is a schematic diagram of another embodiment of a new Buck-Boostconverter.

FIG. 14 is a schematic diagram of another embodiment of a new Buck-Boostconverter.

FIG. 15 is a schematic diagram of another embodiment of a new Buck-Boostconverter.

FIG. 16 is a schematic diagram of another embodiment of a new Buck-Boostconverter.

FIG. 17 is a schematic diagram of another embodiment of a new Buck-Boostconverter.

FIG. 18 is a schematic diagram of another embodiment of a new Buck-Boostconverter.

FIG. 19 is a flowchart of an embodiment of a pass-through mode basedmethod.

FIG. 20 is a schematic diagram of an embodiment of a general-purposecomputer system.

DETAILED DESCRIPTION

It should be understood at the outset that although an illustrativeimplementation of one or more embodiments are provided below, thedisclosed systems and/or methods may be implemented using any number oftechniques, whether currently known or in existence. The disclosureshould in no way be limited to the illustrative implementations,drawings, and techniques illustrated below, including the exemplarydesigns and implementations illustrated and described herein, but may bemodified within the scope of the appended claims along with their fullscope of equivalents.

FIG. 1 illustrates a typical architecture of a power system 100 that maybe used to regulate/control power for electronics equipment, such astelecommunication equipment. The power system 100 may be a DC systemthat receives a plurality of DC voltage inputs (e.g. Input A and InputB) and provides a plurality of regulated DC voltage outputs to aplurality of loads in the electronics equipment to improve reliability.For example, in telecommunication equipment, the input voltages may havea relatively wide voltage range, e.g. from about 38 volts (V) to about72 V, which may cause current and voltage stresses on the components inthe power system. The DC voltage inputs may be supplied by a DC powersource, such as a battery, or by an alternating current (AC) powersource through an AC/DC power converter, which may be located on site,such as on the same platform as the components of the power system 100,or separately at a different site.

The power system 100 may comprise a plurality of power distributionunits (PDUs) 110 and/or power entry modules (PEMs) 120 coupled to theinput voltages and a plurality of circuit cards 130 coupled to the PDUs110/PEMs 120. The power system 100 may also comprise a bus 150 that maybe positioned between the PDUs 110/PEMs 120 and the circuit cards 130,and a fan tray 190 that may be coupled to the bus 150. Each of thecircuit cards 130 may comprise an A/B input combining circuit 132 and abus converter/brick 138. In some designs, a circuit card 130 may alsocomprise an inrush limit circuit 134 and/or an electromagneticinterference (EMI) filter 136, which may be positioned between the A/Binput combining circuit 132 and the bus converter/brick 138.Additionally, a capacitor 192 may be positioned between the busconverter/brick 138 and the inrush limit circuit 134/EMI filter 136, asshown in FIG. 1. The circuit cards 130 may have loads and other powersupplies or power converters to convert the output voltage or the inputvoltage of the bus converter to voltages acceptable to the loads. ThePDUs 110/PEMs 120 may be located on site or on the same platform as thecircuit cards 130, or separately at a different site, for example at thelocation of the power source.

As shown in FIG. 1, a subset of PDUs 110/PEMs 120 may be coupled inparallel between each input (e.g. Input A and Input B) and the bus 150.For instance, a plurality of parallel pairs of PDU 110 and PEM 120 thatare in series may be positioned between each input and the bus 150. Aplurality of circuit cards 130 may be coupled to the bus 150. As such,the input voltages may pass-through PDUs 110/PEMs 120 and may bedistributed to the circuit cards 130 via the bus 150. The bus 150 may bea backplane or a bar bus that transfers the voltages/current from thePDUs 110/PEMs 120 to the circuit cards 130. The fan tray 190 may be usedto control the temperature of components in the system.

At the circuit cards 130, the A/B input combining circuits 132 may beany devices configured to combine the voltages that correspond to thedifferent inputs. Specifically, in the case of multiple inputs, aseparate path may be used to deliver power from each input andsubsequently the power may be combined in the A/B input combiningcircuits 132 on the circuit cards 130. For instance, in the case of twoinputs, Input A and Input B, the A/B input combining circuit 132 maycombine the two corresponding voltages that are received on the bus 150.In other designs, the A/B input combining circuit 132 may combine thevoltages from more than two inputs. Additionally, in some systems, theinrush limit circuits 134 and the EMI filters 136 may be used to providesoft-start and hot swap functions. The capacitor 192 may be used tofurther stabilize the voltage at the bus converter/brick 138.

The bus converters/bricks 138 may be any devices configured to convertor regulate the received voltages to meet the requirements of the loadsin the equipment or provide a suitable input to subsequent powerconverters. For instance, each circuit card 130 may be coupled to aplurality of loads (not shown) that require different voltages/currentsto operate. The bus converters/bricks 138 may also provide isolationbetween the inputs and the loads. On-card power conversion may beimplemented in various approaches. In one approach, the combined andfiltered inputs may be converted using the bus converters/bricks 138 andsubsequently using point-of-load (POL) converters to further regulatethe outputs for the loads. In another approach, the combined andfiltered voltages may be directly regulated using isolated powerconverters in the power system 100.

In the power system 100, the separate delivery paths between the inputsand the circuit cards may be relatively long and may require substantialspace and resources. Further, a relatively wide voltage range may bedelivered to the circuit cards, which may cause substantial stress inthe components on the circuit cards. The stress in the components maycause substantial power loss and/or require more component space, whichmay result in low efficiency, low power density, and/or higher cost.

FIG. 2 illustrates an architecture of another power system 200 that mayimplement one or a plurality of isolated voltage regulators to regulatevoltages to circuit cards in the equipment. Similar to the architectureof the power system 100, the power system 200 may receive a plurality ofDC power/voltage inputs (e.g. Input A and Input B) and provide aplurality of regulated DC voltage outputs to a plurality of loads in theelectronics equipment. However, the power system 200 uses a plurality ofisolated voltage regulators to provide substantially fixed voltages tocircuit cards of the power system 200, and thus reduce voltage andcurrent stress on the components.

In some cases, the quantity of isolated voltage regulators and possiblyother components may exceed the quantity of components necessary for thepower system 200 to function properly. For example, M+N modules orcomponents that include isolated voltage regulators may be used insteadof a minimum quantity of necessary components N (N and M are integers).The additional M components may be redundant components that may improvethe system reliability. Thus, if some components fail, the power system200 may still use at least N components to function properly.

The power system 200 may comprise a plurality of PDUs 210 coupled to theinput voltages, a plurality of isolated voltage regulators 220 coupledto the PDUs 210, and a plurality of circuit cards 230 coupled to theisolated voltage regulators 220. The power system 200 may also comprisea bus or backplane 250 that may be positioned between the isolatedvoltage regulators 220 and the circuit cards 230, and a fan tray 290that may be coupled to the bus 250. On each of the circuit cards 230,there may exist an inrush limit circuit 234 and/or an EMI filter 236coupled to the bus 250, and a bus converter/brick 238 coupled to theinrush limit circuit 234/EMI filter 236. A capacitor 292 may also bepositioned between the bus converter/brick 238 and the inrush limitcircuit 234/EMI filter 236, as shown in FIG. 2. The PDUs 210 and theisolated voltage regulators 220 may be located on site or same platformas the circuit cards 230 or separately at a different site.

As shown in FIG. 2, a pair of PDUs 210 may be coupled between twocorresponding inputs (e.g. Input A and Input B) and an isolated voltageregulator 220, which may be coupled to the circuit cards 230 via the bus250. The isolated voltage regulator 220 may be configured to convert theinput voltages into substantially fixed output voltages to reduce stresson the components of the circuit cards 230. For example, intelecommunications systems, the input voltages may vary from about 38 Vto about 72 V and the output voltages may be fixed at about 45 V or 54V. In this case, the bus converters/bricks 238 may comprise fixed ratiobus converters that convert the fixed voltages from the isolated voltageregulator 220 into suitable voltage values for the point of loadconverters and loads on the circuit cards. The remaining components ofthe power system 200 may be configured substantially similar to thecorresponding components of the power system 100. Using the isolatedvoltage regulator 220 in the power system 200 may increase theefficiency and power density and reduce cost in the circuit cards 230,e.g. in comparison to the power system 100. However, the isolatedvoltage regulator 220 may be complex and have relatively low efficiency.Thus, the overall efficiency of the system may not substantiallyimprove.

Disclosed herein are systems, apparatuses, and methods for supportingand providing high efficiency and high density power system, e.g. incomparison to existing power system architectures, that use voltageregulators for electronics equipment. The power systems may comprise atleast one non-isolated voltage regulator that may convert a voltageinput from a power source into a regulated voltage output. The regulatedvoltage output may be delivered from the non-isolated voltageregulator(s) to at least one circuit card. The non-isolated voltageregulator may be used to control the voltage output within an acceptableor suitable range to reduce the power stress on the load or theelectronics equipment. The non-isolated voltage regulator may beconfigured to operate a substantial amount of time (e.g. during steadystate operation) within a pass-through mode, where the non-isolatedvoltage regulator's switching components (e.g. switches) may not beswitched regularly to improve the power efficiency of the power systemand/or system reliability. Further, a plurality of non-isolated voltageregulators may be combined, e.g. in parallel, to convert a pluralityvoltage inputs for one or a plurality of circuit cards in theelectronics equipments. The voltage regulators may also be configuredfor current sharing on positive leads, negative leads, or both, and mayprovide a combined voltage output.

The non-isolated voltage regulator may comprise a Buck convertercircuit, a Boost converter circuit, a Buck-Boost converter circuit, orcombinations thereof. When the voltage regulator receives a voltageinput above a desired voltage range, the voltage regulator may operatein Buck mode to provide a voltage output that is less than the voltageinput and within the range. Alternatively, if the voltage input to thevoltage regulator is below the desired range, the voltage regulator mayoperate in Boost mode to provide a voltage output that is greater thanthe voltage input and within the range. However, if the voltage input iswithin the desired range, the voltage regulator may operate in thepass-through mode, where the voltage regulator may not substantiallychange the voltage input and thus provide a voltage output that may beclose or about equal to the voltage input.

FIG. 3 illustrates an embodiment of an architecture for a power system300 that may implement a plurality of non-isolated voltage regulatorsand use a pass-through mode to regulate power for electronics equipment.The power system 300 may receive one or a plurality of DC power/voltageinputs (e.g. Input A and Input B) and provide a plurality of regulatedDC voltage outputs to a plurality of loads in the electronics equipment.However, unlike the power system architectures above, the power system300 may use one or a plurality of non-isolated voltage regulators toprovide regulated voltages within a relatively narrow voltage range(with respect to the input voltages) to some components of the powersystem 300 and subsequently to the circuit cards in the equipment.Providing such components with a narrower voltage range than the inputvoltages may reduce the power loss of the components and the voltage andcurrent stresses on the components. The non-isolated voltage regulatorsmay also be less complex and may be configured to have higher efficiencythan the isolated voltage regulators, e.g. the isolated voltageregulators 220. Thus, the power system 300 may have higher efficiency,higher power density, and lower cost than other power systems, such asfor the power system 100 and the power system 200.

The power system 300 may comprise a plurality of PDUs 310 coupled to theinput voltages, a plurality of non-isolated voltage regulators 320coupled to the PDUs 310, and a plurality of circuit cards 330 coupled tothe non-isolated voltage regulators 320. The power system 300 may alsocomprise a bus or back plane 350 that may be positioned between thenon-isolated voltage regulators 320 and the circuit cards 330, and a fantray 390 that may be coupled to the bus 350. Further, on each of thecircuit cards 330 there may exist an inrush limit circuit 334 and/or anEMI filter 336 coupled to the bus 350, a bus converter/brick 338 coupledto the inrush limit circuit 334/EMI filter 336, and a capacitor 392 thatmay be positioned between the bus converter/brick 338 and the inrushlimit circuit 334/EMI filter 336. The components of the power system 300may be arranged as shown in FIG. 3, and may be configured substantiallysimilar to the corresponding components of the power system 300.

However, unlike the power system 200 that uses the isolated voltageregulators 220 to provide fixed voltages to the circuit cards 230, thepower system 300 may use the non-isolated voltage regulators 320 toprovide voltages that have a narrower range than any of the inputvoltages or combination of the input voltages, Input A and Input B, tothe circuit cards 330. Specifically, the non-isolated voltage regulators320 may comprise a Buck converter, a Boost converter, a Buck-Boostconverter, or combinations thereof and accordingly operate in Buck mode,Boost mode, and/or Buck-Boost mode. As such, the non-isolated voltageregulators 320 may increase or decrease the input voltages if the inputvoltages or combined input voltages are not within a desired or narrowrange that is provided to the circuit cards 330.

Additionally, the non-isolated voltage regulators 320 may be configuredto operate in a pass-through mode if the input voltages or combinedinput voltages are within the desired narrow range. In the pass-throughmode, the switching components of the non-isolated voltage regulators320 (e.g. a plurality of switches and/or diodes) may not be switchedregularly, which allows the input voltages to pass to the circuit cards330 without substantial change. The desired narrow range may be set,e.g. by design, to operate the non-isolated voltage regulators 320 mostof the time in the pass-through mode, which may reduce operation powerloss. Therefore, the pass-through mode operation may further improveefficiency and power density in the power system 300. The differentcomponents and different operation modes of the non-isolated voltageregulators 320 are described in further detail below.

FIG. 4 illustrates an embodiment of various operational modes 400 for anon-isolated voltage regulator in a power system, e.g. the non-isolatedvoltage regulator 320 in the power system 300. The various operationalmodes 400 may comprise the pass-through mode and the Buck mode, or theBoost mode, or both. Specifically, an output voltage (Vout) from thenon-isolated voltage regulator may be regulated at about constant valuein the Boost mode and/or the Buck mode and vary similarly to an inputvoltage (Vin) to the voltage regulator in the pass-through mode. Forinstance, Vout may be equal to a minimum of a desired output voltagerange in the Boost mode and to a maximum of the desired output voltagerange in the Buck mode.

FIG. 4 shows the relationship between Vin and Vout in three subsequentzones (e.g. zones in which Vin may move to over time): a Boost zone, apass-through zone, and a Buck zone. In the Boost zone, Vin may be belowthe desired voltage range of the circuit cards or loads. Thus, thenon-isolated voltage regulator may operate in the Boost mode, where Voutmay be greater than Vin. This is represented by a horizontal straightline relationship between Vout and Vin that indicates about constantvalue for Vout at the minimum of the desired voltage range and smallervalues for Vin. In the pass-through mode, Vin may be within the desiredvoltage range for operation. Thus, the non-isolated voltage regulatormay operate in the pass-through mode, where Vout may be about equal toVin. This is represented by a straight line relationship that has aslope of about one and indicates similar Vin and Vout values, whichextend from the minimum to the maximum of the desired voltage range. Inthe Buck zone, Vin may be above the desired voltage range of the circuitcards or loads. Thus, the non-isolated voltage regulator may operate inthe Buck mode, where Vout may be less than Vin. This is represented by asecond horizontal straight line relationship between Vout and Vin thatindicates about constant value for Vout at the maximum of the desiredvoltage range and greater values for Vin.

Many variations in the operational modes are possible. FIG. 5illustrates another embodiment of a various operational modes 500 for anon-isolated voltage regulator. Similar to the various operational modes400, the various operational modes 500 may also comprise thepass-through mode and the Buck mode, or the Boost mode, or both. In thepass-through mode of the various operational modes 500, Vout may besimilar to Vin, as was in the case of the various operational modes 400.However, in the Boost mode and/or the Buck mode of the variousoperational modes 500, Vout may be regulated at varying (e.g.non-constant) values based on Vin (instead of a constant value). Assuch, the Boost mode and/or the Buck mode may provide non-constant Voutbased on Vin. For instance, Vout may be greater than Vin at the minimumof the desired output voltage range in the Boost mode and less than Vinat the maximum of the desired output voltage range in the Buck mode. Inother embodiments, the various operational modes 500 may have differentrelationships between Vout and Vin in any of the operation modes thanthe various operational modes 400 and the various operational modes 500,for example according to the power system requirements. For instance, insome actual designs, the transitions between the pass-through mode andthe Boost/Buck mode(s) may be smoother than is shown in FIG. 4 and FIG.5. Many variations of the operational modes may also be possible.

The desired output voltage range from the non-isolated voltage regulatormay be designed to improve the power efficiency of the power system. Forinstance, increasing the voltage range, such as the difference betweenthe minimum and maximum values, may increase the pass-through timeoperation of the non-isolated voltage regulator and thus reduce powerconsumption in the power system 300. Alternatively, reducing the voltagerange may reduce stress on the electronics components and designcomplexity. Thus, a compromise may be decided to improve overallefficiency and power density. In an embodiment, the output voltage rangeor Vout may be pre-calculated according to Vin, input current, outputpower, other operation condition, or combinations thereof. In anotherembodiment, Vout may be adjusted on-line, e.g. in real time in a dynamicmanner, based on operation parameters such as input current, inputpower, output power, etc. to improve efficiency.

Further, the non-isolated voltage regulator may be configured to operatein the pass-through mode during substantially entire steady stateoperation to improve the steady state efficiency of the system. As such,the non-isolated voltage regulator may operate in Buck mode and/or Boostmode only during relatively short intervals, such as after a primarypower source is lost and until a backup source (e.g. battery) turns onor when there is a temporary voltage surge from the power source. Toimprove the efficiency during Buck/Boost mode(s), the non-isolatedvoltage regulator may be operated in a switched operation mode, e.g.using pulse width modulation, frequency modulation, or other controlmethods to control the voltage regulator switches.

In some cases, the Buck or Boost mode may not be necessary, which maysimplify the circuit design. For example, if the input source issubstantially close to the electronics equipment, then the input voltageat the equipment may not have substantial surges. Thus, the Buck modeoperation and the corresponding components (e.g. Buck convertercomponents) may not be used in the voltage regulator and the voltageregulator may only support the pass-through and Boost modes.

FIG. 6 illustrates an embodiment of a non-isolated voltage regulator 600that may be configured to operate in pass-through mode. The non-isolatedvoltage regulator 600 may comprise a Buck-Boost converter 610, a firstswitch (S1) 612 on a positive power line or lead, and a second switch(S2) 614 on a negative power line or lead. In other embodiments, thenon-isolated voltage regulator 600 may comprise a Buck converter, aBoost converter, or both, for example instead of the Buck-Boostconverter 610. The S1 612 and S2 614 switches may correspond tomechanical switches, such as relays, and/or semiconductor switches, suchas metal-oxide-semiconductor field-effect transistor (MOSFET), bipolarjunction transistor (BJT), insulated gate bipolar transistor (IGBT), orcombinations thereof. The term “switching component” is used togenerically describe switches, diodes, or any other switchingcomponents.

During the pass-through mode, the S1 612 and S2 614 switches may beclosed, which may allow the input voltage/current to bypass theBuck-Boost converter 610 and may provide a similar output voltage fromthe non-isolated voltage regulator 600. In some cases, the switch S1 612and/or S2 614 may comprise a plurality of semiconductor switches thatare configured to block voltage/current in one direction (e.g. left orright) or both directions. In other embodiments, the non-isolatedvoltage regulator 600 may comprise a single switch instead of twoswitches on the positive or negative power line, such as when aplurality of voltage regulators share the same positive or negativepower line. In other embodiments, the Buck-Boost converter 610 or otherconverter may have a built-in pass-through function and thus theexternal switches S1 612 and S2 614 may not be needed. As such, theconverter's built-in switches may be configured to implement thepass-through mode, as described below.

FIG. 7 illustrates an embodiment of a Buck converter 700, which may beused as a non-isolated voltage regulator or a part of the voltageregulator, e.g. in the power system 300. The Buck converter 700 mayimplement the Buck mode operation and have a built-in pass-throughfunction, e.g. based on an internal switch. The Buck converter 700 maycomprise a buck switch (S₁) 708, a freewheeling diode (D₂) 704 and anoutput capacitor (C₂) 706, which is arranged in parallel to the outputvoltage (Vout), as shown in FIG. 7. S₁ may comprise a semiconductorswitch, such as MOSFET, BJT, IGBT, or combinations thereof. D₂ may be asynchronous rectifier or comprise any semiconductor switch instead of adiode. In some embodiments, the Buck converter 700 may also comprise aninput capacitor (C₁) 702.

In the Buck mode operation, S₁ may be used to control current flowto/from an inductor (L₁) 710. Specifically, S₁ may be switched on andoff (or closed and opened) in an alternating manner, for instance usingcontinuous wave (CW) pulses as control signals to the switch, to connectL₁ to Vin, and thus store energy in L₁ and discharge the stored energyfrom L₁ onto Vout, respectively. As such, Vout may vary with respect toVin in a linear manner to the duty cycle for switching on (or closing)and switching off (or opening) S₁. S₁ may also act to prevent a suddenrise in voltage due to unloading. Since Vout may not exceed Vin in theBuck mode operation, the Buck converter is referred to as a step-downconverter.

In the pass-through mode operation, S₁ may be kept switched on or closed(and is not switched back off or opened) to allow the input current topass-through from input to output. Thus, Vin and Vout may be close orabout equal, e.g. the difference between Vin and Vout may be due to someresistance in the circuit. Further, L₁ and C₂ may form a filter that mayreduce noise in the circuit and its input and output. S₁ may also beused as a protection switch (e.g. to implement a protection function) toswitch the converter or voltage regulator off when a faulty conditionoccurs, for example that is associated with temperature, current, orvoltage. In some embodiments, S₁ may be controlled to turn on relativelyslowly by slowly increasing the gate drive voltage of S₁ or the controlduty cycle for S₁ to bring up Vout relatively slowly without suddenincreases in voltage value, and thus provide soft-start to the output.Additionally, in the pass-through mode, the gate drive voltage of S₁ maybe adjusted to provide more system functions, such as noise filtering,current sharing between multiple voltage regulators, or other functions.

FIG. 8 illustrates an embodiment of a Boost converter 800, which may beused as a non-isolated voltage regulator or a part of the voltageregulator, e.g. in the power system 300. The Boost converter 800 mayimplement the Boost mode operation and have a built-in pass-throughfunction, e.g. based on an internal switch. The Boost converter 800 maycomprise a boost switch (S₄) 804 and an output capacitor (C₂) 806, whichis in parallel to an output voltage (Vout), as shown in FIG. 8. A boostinductor (L₁) 808 and a second switch (S₃) 810 are also shown. S₃functions as a synchronous rectifier and may be changed to a diode. Insome embodiments, the Boost converter 800 may also comprise an inputcapacitor (C₁) 802.

In the Boost mode operation, S₄ may be used to control current flowto/from L₁. Specifically, S₄ may be switched on and switched off (orclosed and opened) in an alternate manner, for instance using CW pulsesas control signals to the switch, to connect L₁ to Vin and thus storeenergy in L₁ and discharge the stored energy from L₁ on to Vout,respectively. S₃ may act also to prevent sudden rise in voltage due tounloading. Since Vout exceeds Vin in the Boost mode operation, the Boostconverter is referred to as a step-up converter.

In the pass-through mode operation, S₄ may be kept switched off oropened (and is not switched back on or closed) to allow the inputcurrent to pass-through from input to output. Thus, Vin and Vout may beclose or about equal, e.g. the difference between Vin and Vout may bedue to some resistance in the circuit. Further, L₁ and C₂ may form afilter that may reduce noise in the circuit and its input and output.Additionally, in the pass-through mode, the gate drive voltage of S₃ maybe adjusted to provide more system functions, such as noise filtering,current sharing between multiple voltage regulators, or other functions.

In an embodiment, a Buck converter and Boost converter, such as the Buckconverter 700 and the Boost converter 800, may be combined in series,e.g. in a voltage regulator, to provide both the Buck mode operation andthe Boost mode operation. Alternatively, a Buck-Boost converter may beused in the voltage regulator to provide both the Buck mode and Boostmode operations. FIG. 9 illustrates an embodiment of a Buck-Boostconverter 900, which may be used as a non-isolated voltage regulator ora part of the voltage regulator, e.g. in the power system 300. TheBuck-Boost converter 900 may implement the Buck mode operation and theBoost mode operation and may have a built-in pass-through function.

The Buck-Boost converter 900 may comprise an input capacitor (C₁) 902, abuck switch (S₁) 910, a freewheeling diode (D₂) 904, a boost switch (S₄)906, an inductor (L₁) 912, a boost diode (D₃) 914, and an outputcapacitor (C₂) 908, which is in parallel to the output voltage (Vout),as shown in FIG. 9. The negative power lead may be used as a commonreturn or a ground for both input and output. Additionally, theBuck-Boost converter 900 may comprise a control, monitor, and drivecircuit 990, which may provide CW pulses as separate control signals foreach of S₁ 910 and S₄ 906.

The Buck-Boost converter 900 may operate substantially similar to theBuck converter 700 and the Boost converter 800 to provide the Buck mode,Boost mode, and pass-through mode operations. As such, Vout may begreater than, about equal to, or less than Vin according in the Boostmode, pass-through mode, and Buck mode, respectively.

In the pass-through operation mode, S₁ and D₃ may be kept switched onand D₂ and S₄ may be kept switched off to allow the input current topass-through from input to output. In the Buck mode operation, S₄ may bekept switched off to operate the Buck-Boost converter 900 as a Buckconverter. As such, S₁ may be used as the control switch and D₂ may beused as the freewheeling device. In the Boost mode operation, S₁ may bekept switched on (and D₂ may be switched off) to operate the Buck-Boostconverter 900 as a Boost converter. As such, S₄ may be used as thecontrol switch and D₃ may be used as the freewheeling device.Alternatively, all switches, S₁, D₂, D₃, and S₄ may be switched on andoff in a sequence that operates the Buck-Boost converter 900 as abuck-Boost converter.

FIG. 10 illustrates another embodiment of a Buck-Boost converter 1000,which may be used as a non-isolated voltage regulator or a part of thevoltage regulator. Similar to the Buck-Boost converter 900, theBuck-Boost converter 1000 may implement the Buck mode operation and theBoost mode operation and may have a built-in pass-through function. TheBuck-Boost converter 1000 is similar to the buck-boost converter 900.However, the diodes D₂ and D₃ in the Buck-Boost converter 900 arereplaced with the switches S₂ 1004 and S₃ 1014, which function assynchronous rectifiers in the Buck-Boost converter 1000. Additionally,the Buck-Boost converter 1000 may comprise a control, monitor, and drivecircuit 1090 that provides CW pulses as separate control signals foreach of S₁, S₂, S₃, and S₄.

FIG. 11 illustrates another embodiment of a Buck-Boost converter 1100,which may be used as a non-isolated voltage regulator or a part of thevoltage regulator. Similar to the Buck-Boost converters above, theBuck-Boost converter 1100 may implement the Buck mode operation and theBoost mode operation and may have a built-in pass-through function. TheBuck-Boost converter 1100 is similar to the buck-boost converter 1000.However, components S₁ 1110, L₁ 1112, and S₃ 1114, are moved to thenegative path, so the positive power lead (instead of the negative powerlead) may be used as the common return or ground for both input andoutput. This may be beneficial in some systems, such as in negativeinput voltage systems, for example in many 48 V based telecommunicationsystems. Additionally, the Buck-Boost converter 1100 may comprise acontrol, monitor, and drive circuit 1190 that provides separate controlsignals for each of S₁ 1110, S₂ 1104, S₃ 1114, and S₄ 1106. In otherembodiments, the switches S₂ 1104 and S₃ 1114 may be replaced by thediodes D₂ and D₃.

In some applications, the power requirements of the electronicsequipment may be substantially high. To meet the high power requirementsin such applications, a plurality of converters or voltage regulatorsmay be coupled in parallel to provide a plurality of output voltages ora combine output voltage, e.g. using a plurality of input voltages or acombined input voltage, and thus increase the output power. In somecases, a plurality of converters 700, 800, 900, 1000, or 1100 may becombined in parallel to establish a multi-phase converter. As such, eachconverter may operate as a phase whose switches' state is determined incoordination with the switching states of switches in the remainingconverters. The switching state of each converter's switches may becontrolled separately using a plurality of corresponding controlsignals. The different control signals for the different phases may beapplied in a synchronous manner with respect to each other to establishmulti-phase operation.

In multi-phase or multi-converter applications, current sharing betweenthe different phases, converters, or voltage regulators may beadvantageous. For instance, current sharing may be achieved bycontrolling the duty cycles or the frequencies of the control signalsfor the different phases. Typically, current sharing schemes may beimplemented using one lead (e.g. positive or negative lead) in anon-isolated converter since the other lead may be a common return orground. However, in some cases, both leads of a converter (e.g. positiveand negative leads) may have limited current carrying capability, andthus current sharing on both leads may be needed, so the currents on thepositive lead and on the negative lead of a converter, or currents onsimilar leads in the multiple converters in parallel, can be controlledto be substantially the same. Therefore, it may be advantageous to placesome of the components of the converters on both leads to allow currentsharing on both leads and improve the overall current carryingcapability of the converter.

FIG. 12 illustrates an embodiment of a Buck-Boost converter 1200, whichmay support current sharing on both positive and negative power leads.Similar to the Buck-Boost converters above, the Buck-Boost converter1200 may implement the Buck mode operation and the Boost mode operationand may have a built-in pass-through function. The Buck-Boost converter1200 may comprise an input capacitor (C₁) 1202, a buck switch (S₁) 1210,a freewheeling synchronous rectifier switch (S₂) 1204, an inductor (L₁)1212, a boost switch (S₄) 1206, a boost synchronous rectifier switch(S₃) 1214 and an output capacitor (C₂) 1208. Additionally, theBuck-Boost converter 1200 may comprise a control, monitor, and drivecircuit 1290 that provides separate control signals for each of S₁, S₂,S₃, and S₄. The components of the Buck-Boost converter 1200 may beconfigured and operated substantially similar to the correspondingcomponents of the Buck-Boost converters 1000 and 1100.

The components S₁, L₁, and S₃ may be distributed between the positiveand negative leads instead of a single lead, which may allow currentsharing on both leads. For instance, the Buck-Boost converter 1200 maybe used in a multi-phase or multi-converter configuration for high powercommunications systems. Accordingly, a plurality of Buck-Boostconverters 1200 and/or similar converters may be coupled in parallel ina multi-phase, multi-converter, or multi-voltage regulator system. Insuch configurations, the gate drive voltages of S₁ and S₂ may becontrolled to regulate the drops in the corresponding voltages and thusadjust relatively the current on each of the leads. This current sharingand current balancing scheme may be necessary in the pass-through modeoperation since other active control means may not be available tocontrol the current distribution on the leads. Alternatively, the gatedrive duty cycles of S₁ and S₂ may be controlled to adjust relativelythe current on each of the leads.

FIG. 13 illustrates another embodiment of a Buck-Boost converter 1300,which may support current sharing and split inductor function on bothpositive and negative power leads. Similar to the Buck-Boost convertersabove, the Buck-Boost converter 1300 may implement the Buck modeoperation and the Boost mode operation and may have a built-inpass-through function. The Buck-Boost converter 1300 is similar to theBuck-Boost converter 1200, but two inductors (L₂) 1312 and (L₁) 1316 areused, one on the positive path from positive input to the positiveoutput and the other on the negative path from negative input to thenegative output. The Buck-Boost converter 1300 may also comprise acontrol, monitor, and drive circuit 1390 that provides separate controlsignals for each of S₁ 1310, S₂ 1304, S₃ 1314, and S₄ 1306. Thecomponents of the Buck-Boost converter 1300 may be configured andoperated substantially similar to the corresponding components of theBuck-Boost converters 1200. As such, the components S₁ and S₃ may bedistributed between the positive and negative leads instead of a singlelead, which may allow current sharing on both leads. Additionally, theinductor function in the Buck-Boost converter 1300 may be split betweenboth positive and negative paths using two inductors L₁ 1316 and L₂ 1312on separate leads instead of one inductor on a single path, which mayallow better current sharing of the power leads.

FIG. 14 illustrates another embodiment of a Buck-Boost converter 1400,which may support current sharing and comprise coupled inductors on bothpositive and negative power leads. Similar to the Buck-Boost convertersabove, the Buck-Boost converter 1400 may implement the Buck modeoperation and the Boost mode operation and may have a built-inpass-through function. The Buck-Boost converter 1400 is similar to theBuck-Boost Converter 1300. The components of the Buck-Boost converter1400 may be configured and operated substantially similar to thecorresponding components of the Buck-Boost converters 1300. However, thetwo inductors L₁ 1412 and L₂ 1413 on the negative and positive leads,respectively, may be coupled to each other and thus provide mutualinductance. The coupling of the two inductors may be advantageously usedto improve the performance of the converter, and/or to reduce the sizeof the converters as two coupled inductors can be physically implementedas one component. In other embodiments, such as in multi-phaseconverters, the inductors in different phases (adjacent converters) mayalso be coupled. Other variations for distributing the inductors and/orswitches on both positive and negative leads may also be used to improvesystem operation and design as needed.

Any of the converters above may be combined in parallel to combineoutput power to electronics equipments and/or provide current sharingand balancing, such as in high power systems and/or multi-phaseapplications. In other embodiments, a Buck converter and a Boostconverter may be combined in series and the components on bothconverters may be distributed on both positive path and negative pathalso to support current balancing on both positive and negative leads.

FIG. 15 illustrates an embodiment of a Buck-Boost converter 1500, whichmay comprise a Buck converter and a Boost converter in series andsupport current balancing on both leads. The Buck-Boost converter 1500may implement the Buck mode operation and the Boost mode operation andmay have a built-in pass-through function. The Buck-Boost converter 1500may comprise an input capacitor (C₁) 1502, a freewheeling switch (S₂)1504, an intermediate capacitor (C₃) 1506, a boost switch (S₄) 1507, andan output capacitor (C₂) 1508, a buck switch (S₁) 1510, an inductor (L₁)1512, a second inductor (L₂) 1513, and a fourth switch (S₃) 1514. TheBuck-Boost converter 1500 may also comprise a control, monitor, anddrive circuit 1590 that provides control signals for S₁, S₂, S₃, and S₄.

The components C₁, S₂, C₃, S₁, and L₁ may correspond to the Buckconverter section of the Buck-Boost converter 1500 and the componentsC₃, S₄, C₂, L₂, and S₃ may correspond to the Boost converter section ofthe Buck-Boost converter 1500. As such, S₁, L₁, L₂, and S₃ may bedistributed on both positive path and negative path to help currentsharing of the power leads. For example, S₁, and L₁ may be positioned onthe negative path and L₂ and S₃ may be positioned on the positive path.Additionally, S₁ and S₂ in the Buck converter section and S₃ and S₄ inthe Boost converter section may be controlled, e.g. in a synchronousmanner, using the same control, monitor, and drive circuit 1590. Thus,the combined control in the Buck converter and Boost converter sectionsmay regulate current balancing on both leads in synchronization. In someembodiments, the Buck-Boost converter 1500 may be coupled to anotherconverter in parallel and controlled to provide current sharing of allpower leads.

FIG. 16 illustrates another embodiment of a Buck-Boost converter 1600that comprises a Buck converter and a Boost converter in series andsupport current balancing on both leads. The Buck-Boost converter 1600may implement the Buck mode operation and the Boost mode operation andmay have a built-in pass-through function. The Buck-Boost converter 1600is similar to the Buck-Boost converter 1500. The components of theBuck-Boost converter 1600 may be arranged and configured substantiallysimilar to the corresponding components of the Buck-Boost converter1500. However, the control of the Buck converter section can beindependent of the control of the Boost converter section.

The Buck-Boost converter 1600 may comprise a first control, monitor, anddrive circuit 1690 that provides control signals for S₁ 1610 and S₂ 1604in the Buck converter section and a second control, monitor, and drivecircuit 1692 that provides separate control signals for S₃ 1614 and S₄1606 in the Boost converter section. As such, S₁ 1610 and S₂ 1604 in theBuck converter section and S₃ 1614 and S₄ 1606 in the Boost convertersection may be controlled independently using the separate controlsignals, and the design of the converter may be simplified. S₂ 1604and/or S₃ 1614 are shown as synchronous rectifiers in FIGS. 15 and 16but may be replaced by diodes (e.g. D₂ and/or D₃) in other embodiments.Further, the Boost converter section may be placed at the input side andthe Buck converter section may be placed at the output side in reverseto the order shown in FIGS. 15 and 16.

In some power systems, a plurality of power inputs may be combinedbefore the voltage regulator stage or after the voltage regulator stage.Alternatively, in some embodiments, the inputs may be combined in thevoltage regulator stage. Combining the inputs before or within thevoltage regulator stage may be advantageous, since a single set of powerdelivery components and connections may be used to deliver the powerfrom the combining point, which may reduce cost and improve powerefficiency. The inputs may be combined using a plurality of diodes,controlled switches, and/or other combination devices.

FIG. 17 illustrates an embodiment of a Buck-Boost converter 1700, whichmay combine a plurality of inputs. The Buck-Boost converter 1700 mayimplement the Buck mode operation and the Boost mode operation and mayhave a built-in pass-through function. The Buck-Boost converter 1700 issimilar to the Buck-Boost converter 1300, but has the addition ofcombining diode (DC1) 1715 for a first input (Input A) and a secondcombining diode (DC2) 1716 for a second input (Input B). The diodes DC11715 and DC2 1716 may be configured to receive and select Input A and/orInput B. For instance, if both Input A and Input B are received, e.g. atabout the same time, then the combining diodes DC1 1715 and DC2 1716 mayselect the input that corresponds to a higher voltage value (e.g. morenegative voltage) as the active input to the converter. Alternatively,if only one of the inputs is received, e.g. at a time instance, then thediodes may pass that input to the converter. This combining scheme toselect an active input to the converter may improve the reliability ofthe power system. In other embodiments, the diodes DC1 1715 and DC2 1716may be replaced by corresponding switches, such as Power MOSFETs toselect the active input. The switches may also be controlled to provideuseful system functions, such as filtering and/or current sharingbetween different converters or voltage regulators. Further, the inputsmay be coupled on a single lead, e.g. positive lead, directly as shownin FIG. 17 or via combination devices on both leads in otherembodiments. Although, only two diodes for two inputs are shown in FIG.17, in other embodiments, the Buck-Boost converter 1700 may comprise anyquantity of diodes for a plurality of corresponding inputs.

In some embodiments, a plurality of converters or voltage regulators maybe coupled in parallel and configured as a redundant voltage regulatorsystem. As such, if one or more converters or voltage regulators fail,the redundant voltage regulator system may still provide power output tothe end system. In one embodiment, the redundant voltage regulatorsystem may comprise an ORing diode or an ORing switch, such as MOSFET,which may be coupled to the output of each of the coupled converters.The ORing diode or switch may be configured to receive and select outputfrom any of the coupled converters.

FIG. 18 illustrates an embodiment of a Buck-Boost converter 1800, whichmay combine a corresponding output (Vout) with the output of anothercoupled converter (not shown) via an ORing diode. The Buck-Boostconverter 1800 may also combine a plurality of inputs. The Buck-Boostconverter 1800 may implement the Buck mode operation and the Boost modeoperation and may have a built-in pass-through function. The Buck-Boostconverter 1800 is similar to the Buck-Boost converter 1700, but has theaddition of an ORing diode (Do) 1818, e.g. on the positive output leadto combine output power from a plurality of converters. In otherembodiments, Do 1818 may be replaced by an ORing switch. Alternatively,Do 1818 may be removed and the output of the Buck-Boost converter 1800may be directly combined with the output of any other converter that maybe coupled to the output of the Buck-Boost converter 1800.

In another embodiment, DC1 1815 and DC2 1816 may be moved to the outputof two corresponding converters, e.g. similar to the Buck-Boostconverter 1800, and in such case the output ORing diode 1818 may not beneeded. As such, each input may be regulated or converted by a separateconverter and then combined at a common output. Thus, if an input failsor is not received in any of the converters, the corresponding convertermay not output power but the remaining converter(s) may still outputpower. However, in this scheme, multiple sets of converters, e.g. onefor each input, may be needed, which may increase system cost and spacerequirement. In some embodiments, the switch or diode in the convertermay be used, e.g. as an ORing device, to combine output power. Forexample, in any of the converters above, S₃ 1814 or D₃ may be use as theORing device, which may improve system reliability without substantiallyincreasing cost or reducing efficiency.

FIG. 19 illustrates an embodiment of a pass-through mode based method1900, which may be implemented using any of the voltage regulators orconverters above. Based on the method 1900, the converter or voltageregulator may operate most of the time or a substantial amount of theoperation time in the pass-through mode. During the pass-through mode,the circuit switches may not be active and the power/voltage output maybe about equal to or close to the power/voltage input and within atolerated voltage range. As such, the method 1900 may improve powerconsumption and power efficiency and density in the power systemcomponents.

The method 1900 may begin at block 1902, where an input voltage may bereceived at a converter (or a voltage regulator). The input voltage maybe received from a single power source, a combined power source, or maybe selected from a plurality of received inputs from a plurality ofpower sources. At block 1910, the method 1900 may determine whether thereceived input voltage is within a determined voltage range. Thedetermined voltage range may be selected to reduce power consumption andincrease power efficiency and density in the system. For example,increasing the voltage range may increase the total operation time ofthe pass-through operation mode, and thus reduce power consumption.Additionally, the voltage range may be limited to avoid receivingsubstantially high voltage values, which may cause substantial stress onthe circuits and/or electronics equipment, and substantially low voltagevalues, which may not be suitable to operate the circuits and/orelectronics equipment.

The method 1900 may proceed to block 1920 if the condition in block 1910is met. Otherwise, the method 1900 may proceed to block 1930. At block1920, the converter (or voltage regulator) may be operated in thepass-through mode, and the method 1900 may then return to block 1902 toreceive new input voltage. As such, the converter switches may beconfigured in a fixed or constant on or off state, e.g. may not beswitched on and off in a continuous or alternating manner, to allow theinput voltage to pass substantially unchanged. At block 1930, the method1900 may determine whether the input voltage is below a minimum voltagevalue (or threshold) of the determined voltage range. The method 1900may proceed to block 1940 if the condition in block 1930 is met.Alternatively, if the input voltage is above a maximum voltage value (orthreshold) of the determined voltage range, then the method 1900 mayproceed to block 1950.

At block 1940, the converter (or voltage regulator) may be operated inthe Boost mode, and the method 1900 may then return to block 1902. Assuch, the converter switches may be controlled and switched, e.g. in acontinuous or alternating manner, to provide an output voltage that isgreater than the input voltage and within the determined voltage range.At block 1950, the converter (or voltage regulator) may be operated inthe Buck mode, and the method 1900 may then return to block 1902. Assuch, the converter switches may be controlled and switched to providean output voltage that is less than the input voltage and within thedetermined voltage range. In some embodiments, the Block mode or theBoost mode operation may not be necessary. Therefore, the method 1900may not implement the Buck mode in Block 1940 or the Boost mode in block1950.

The control systems described above may be implemented on anygeneral-purpose network equipment, such as a computer or router withsufficient processing power, memory resources, and network throughputcapability to handle the necessary workload placed upon it. FIG. 20illustrates a typical, general-purpose network equipment 2000 suitablefor implementing one or more embodiments of the components disclosedherein. The network equipment 2000 includes a processor 2002 (which maybe referred to as a central processor unit or CPU) that is incommunication with memory devices including secondary storage 2004, readonly memory (ROM) 2006, random access memory (RAM) 2008, input/output(I/O) devices 2010, and network connectivity devices 2012. The processor2002 may be implemented as one or more CPU chips, or may be part of oneor more application specific integrated circuits (ASICs).

At least one embodiment is disclosed and variations, combinations,and/or modifications of the embodiment(s) and/or features of theembodiment(s) made by a person having ordinary skill in the art arewithin the scope of the disclosure. Alternative embodiments that resultfrom combining, integrating, and/or omitting features of theembodiment(s) are also within the scope of the disclosure. Wherenumerical ranges or limitations are expressly stated, such expressranges or limitations should be understood to include iterative rangesor limitations of like magnitude falling within the expressly statedranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4,etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example,whenever a numerical range with a lower limit, R_(l), and an upperlimit, R_(u), is disclosed, any number falling within the range isspecifically disclosed. In particular, the following numbers within therange are specifically disclosed: R=R_(l)+k*(R_(u)−R_(l)), wherein k isa variable ranging from 1 percent to 100 percent with a 1 percentincrement, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5percent, . . . , 50 percent, 51 percent, 52 percent, . . . , 95 percent,96 percent, 97 percent, 98 percent, 99 percent, or 100 percent.Moreover, any numerical range defined by two R numbers as defined in theabove is also specifically disclosed. Use of the term “optionally” withrespect to any element of a claim means that the element is required, oralternatively, the element is not required, both alternatives beingwithin the scope of the claim. Use of broader terms such as comprises,includes, and having should be understood to provide support fornarrower terms such as consisting of, consisting essentially of, andcomprised substantially of. Accordingly, the scope of protection is notlimited by the description set out above but is defined by the claimsthat follow, that scope including all equivalents of the subject matterof the claims. Each and every claim is incorporated as furtherdisclosure into the specification and the claims are embodiment(s) ofthe present disclosure. The discussion of a reference in the disclosureis not an admission that it is prior art, especially any reference thathas a publication date after the priority date of this application. Thedisclosure of all patents, patent applications, and publications citedin the disclosure are hereby incorporated by reference, to the extentthat they provide exemplary, procedural, or other details supplementaryto the disclosure.

While several embodiments have been provided in the present disclosure,it should be understood that the disclosed systems and methods might beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted, or not implemented.

In addition, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as coupled or directly coupled orcommunicating with each other may be indirectly coupled or communicatingthrough some interface, device, or intermediate component whetherelectrically, mechanically, or otherwise. Other examples of changes,substitutions, and alterations are ascertainable by one skilled in theart and could be made without departing from the spirit and scopedisclosed herein.

What is claimed is:
 1. A power system comprising: a non-isolated voltageregulator configured to couple to an input voltage and produce an outputvoltage, wherein the non-isolated voltage regulator is in a powerdistribution system and configured to boost the input voltage when theinput voltage is less than a minimum output voltage, to reduce the inputvoltage when the input voltage is greater than a maximum output voltage,and to pass-through the input voltage when the input voltage is greaterthan or equal to the minimum output voltage and less than or equal tothe maximum output voltage.
 2. The power system of claim 1, wherein thenon-isolated voltage regulator is coupled to a circuit card via abackplane or bus.
 3. The power system of claim 2, and wherein themaximum output voltage and the minimum output voltage of thenon-isolated voltage regulator are configured such that the non-isolatedvoltage regulator operates in a pass-through mode during substantiallymost of operation time.
 4. The power system of claim 2, wherein thenon-isolated voltage regulator is coupled to the circuit card on thesame platform.
 5. The power system of claim 1, wherein the minimumoutput voltage and the maximum output voltage are different.
 6. Thepower system of claim 1, wherein boosting the input voltage producessubstantially the same output voltage regardless of the input voltage.7. The power system of claim 1, wherein reducing the input voltageproduces substantially the same output voltage regardless of the inputvoltage.
 8. The power system of claim 1, wherein boosting the inputvoltage produces an output voltage that increases with an increase inthe input voltage.
 9. The power system of claim 1, wherein reducing theinput voltage produces an output voltage that decreases with a decreasein the input voltage.
 10. The power system of claim 1, wherein a maximumboosted output voltage is not equal to a minimum passed through outputvoltage.
 11. The power system of claim 1, wherein a minimum reducedoutput voltage is not equal to a maximum passed through output voltage.12. A non-isolated voltage regulator comprising: a positive input lead;a positive output lead coupled to the positive input lead; a negativeinput lead; a negative output lead coupled to the negative input lead; afirst switching component positioned between the positive input lead andthe positive output lead; and a second switching component positionedbetween the negative input lead and the negative output lead.
 13. Thenon-isolated voltage regulator of claim 12 further comprising: a firstinductor coupled between the positive input lead and the positive outputlead; and a second inductor coupled between the negative input lead andthe negative output lead.
 14. The non-isolated voltage regulator ofclaim 13, wherein at least one of the first switching component, thesecond switching component, the third switching component, and thefourth switching component is a diode.
 15. The non-isolated voltageregulator of claim 13, wherein the first inductor and the secondinductor are coupled to each other.
 16. The non-isolated voltageregulator of claim 13 further comprising: a first control circuit forthe first switching component and the second switching component, and asecond control circuit for the third switching component and the fourthswitching component, wherein the first control circuit and the secondcontrol circuit operate independently.
 17. A method comprising:controlling a first gate voltage in a first switching component on afirst power lead of a first non-isolated voltage regulator; andcontrolling a second gate voltage in a second switching component on asecond power lead of the first non-isolated voltage regulator, whereineach of the first power lead and the second power lead shares currentwith a third power lead of a second non-isolated voltage regulatorcoupled in parallel to the first non-isolated voltage regulator.
 18. Themethod of claim 17, wherein controlling the first gate voltage, thesecond gate voltage, or both supports a soft-start function.
 19. Themethod of claim 17, wherein controlling the first gate voltage, thesecond gate voltage, or both supports a filtering function.
 20. Themethod of claim 19, wherein the filtering function is supported bycontrolling the first switching component or the second switchingcomponent to enable an inductor and a capacitor to reduce noise in anoutput voltage.
 21. The method of claim 17, wherein controlling thefirst gate voltage, the second gate voltage, or both supports aprotection function.
 22. The method of claim 17, wherein controlling thefirst gate voltage, the second gate voltage, or both is accomplished byadjusting a voltage amplitude.
 23. The method of claim 17, whereincontrolling the first gate voltage, the second gate voltage, or both isaccomplished by adjusting a duty cycle.